Bituminous street-pavement.



No. 695,422. Q a 1 F. J. WARREN. 1

BITUMINUUS STREET PAVEMENT.

(Applicati on filed Jan. 10, 1902.) (No Model.)

m: NORRIS Finns co., Pnm'qurna. WASHINGYON, DV 6.

Patented Mar. ll,

UNITE STATES FREDERICK J. \VARREN, OF

NEWTON, MASSACHUSETTS.

BITUMINOUS STREET-PAVEMENT.

SPECIFICATION forming part of Letters Patent No. 695,422, dated March' l l, 1902.

Application filed January 10, 1902. Serial No. 89,163. (lie specimens) To all whom, it 11mg concern.-

Be it known that I, FREDERICK J. \VARREN, a citizen of the United States, residing at Newton, in the county of Middlesex and State of Massachusetts, have invented a new and useful Improvement in Asphalt, Bituminous Macadam, Coal-Tar, and other Bituminous Street-Pavements, of which the following is a full, clear, and exact description, reference being had to the accompanying drawings, forming a part of this specification, in explaining its nature.

The invention relates to the type of streetpavement lia ving a wearing-section consisting of a bituminous mixture containing from four to fifteen per cent., by weight, of bitumen to eighty-five to ninety-six per cent, by weight, of mineral, such as stone, gravel, sand, clay, loam, &c. ing-section of such pavements as now ordinarily laid have a fine cellular or honeycomb structure, sometimes visible to the naked eye and sometimes so fine as to be visible only by the aid of a magnifying-glass or a microscope. This fine cellular or honeycomb effect is produced, I believe, because such pavements chill before their final compression to such an extent that a continuous homogeneous water and weather proof surface .is not secured. However this maybe, the effect of this fine cellular or honeycombed condition is to produce a crumbling of the wearing-section and a disintegration of the surface under traffic. This is due, I believe, to the fact that the cellular or honeycombed structure being open to the influences of the weather furnishes means whereby the pavement below its surface is subject to attack and disintegration by water and the circulation of air in the more or less minute'cel1s,andI have discovered that theseinj urious effects of this cellular or honeycomb structure of pavement is entirely overcome by sealin g the cells in such a manner as to prevent air and moisture from reaching them and circulating in-them. To so seal the cells and protect the wearing-surface of the pavement,- I apply to the wearingsurface of the pavement after it has been finished in the ordinary manner a thin coat of relatively pure bitumen inliquid form, sprinkled, brushed, poured, orrubbed over the sur- 1 have ascertained that the wearface,so as to unite with it and completely close the cells thereof, andthusjprotectthe wearing-section of the'pavement from the exposure which it receives when the cells are open. I havei'urther discovered that this greatly adds to, preserves, and prolongs the life of the pavement. It also provides a cement which at the time of the application is sticky and adhesive and on which can then be spread a thin coat of stone, gravel, orstone chips, which by rolling will adhere to the pavement as laid and furnish-it with any desired color or roughness of surface desired. It thus becomes possible to use for such" a surfacing flint orother expensive but durable material, thus presenting to the wear of traffic a material which otherwise could not be economicallyemployed' I will now describe theinvention in connection with the drawings forming apart of this specification.

Figure 1 1s a view in cross vertical section of a street-pavement or roadway having the features of my invention. liig. 2 is a view insection, enlarged, representing a modification thereof. Fig. 3 is a view in vertical section, enlarged,of a portion of the wearingsection of Fig. 1.

Referring to the drawings, A represents the ordinary wearing or upper section of an asphalt, bituminous macadam, coal-tar, or other form of bituminous pavement and'which usually comprises a bituminous mixture of bitumen and mineral of the proportions and kinds I have already indicated. This section, of the pavement isin' the complete or finished form in which such paveme ts are now laid, and so laid it usually pos esses a fine or minute cellular or honeycomb formation extending more or less through it, and which possesses a capacity for receiving and holding moisture, water, and air. The pres ence of moisture or air below the surface of the wearing-section tends to gradually rot it and disintegrate it, so that it loses its tenacity and strength, and therefore scales and disintegrates more rapidly than it should.

It is desirable to protectthe life of the upper surface of the wearing-section, and if this life can be maintained in its original intensity it will withstand much longer the wearing effect of traflic upon it than if it had become weak-ened. 3y sealing the cells in the wearing-section, which are in the nature of pores, the upper surface of the wearing-section becomes so protected from the injurious elfects of atmospheric exposure that its life is continued and its resisting power to traific is also continued. The pores are so fine that they cannot be shown in the drawings, and therefore cannot be lettered.

The thin coating B is of relatively pure bitumen in a liquid form, and I prefer to combine it with the surface by brushing or rubbing and so as to seal the cells and pores by a water and weather proof sealing which prevents the absorption by the pores of moisture or aii or other deleterious substance from the atmosphere. This relatively pure coating when first applied to the surface of the pavement is sticky and adhesive and will act to receive and unite to the surface of the pavement a thin coat of sand, gravel, or stone chips when rolled into it, and there will then be provided the pavement not only the means for sealing its cells or pores, but also means for furnishing it with a surfacing more or less rough, as may be desired, and of any wished-for color. It also permits the application to the wearing-section of a mineral highly desirable for a wearing-surface; but it cannot be combined with a wearing-section because of expense. I refer to flint or other relatively expensive durable material.

I would state that the bituminous coating may be applied in either a hot or cold state.

The advantages of the invention need not further be enlarged upon.

Having thus fully described my invention, I claim and desire to secure by Letters Patent of the United States- 1. The application to the wearing-surface of a bituminousstreet-pavement having a cellular or porous character, for the purpose of closing its pores and preserving its life, of a cell or pore sealing coating of bituminous cement.

2. The application to the wearing-surface of a bituminous street-pavement of a thin coating of bituminous cement applied thereto in a plastic condition and combined while plastic with suitable stone, gravel or sand of a character to provide a roughness to the surface of the pavement.

3. The application to the surface of a bituminous street-pavement having a cellular or porous character, for the purpose of closing its pores, preserving its life and providing a wearing-surface of a more durable character than it, of a thin cell-sealing eoatingoi bituminous cement combined and united with mineral ol. a ilinty or other hard character.

FREDERICK .T. WARREN.

Witnesses:

F. F. RAYMOND, 2d, J. M. DOLAN. 

